Jon Bernthal was stunned by Shia LaBeouf's horrific method acting techniques before movie

Shia LaBeouf managed to leave quite a lasting impression on his co-star Jon Bernthal after really throwing himself into his role for the 2014 war film they both starred in.

The Transformers star, 37, chose to use the technique of method acting to ensure that he did his character justice, but the rest of the cast were left pretty stunned by the lengths he actually ended up going to.

LaBeouf isn't the first to make an impression with method acting, with stars like Jared Leto having his own eyebrow raising antics on the set of Morbius.

It seems to be a case of different strokes for different folks, but LaBeouf apparently managed to take the method acting biscuit while on the set of Fury alongside Bernthal, Brad Pitt, Logan Lerman and Michael Peña.

If you aren't aware, method acting basically means that between rehearsals, the lead up to filming and actually shooting the movie, the actor tries to become the person they are playing.

Mentally, physically and emotionally, they try and embody the person they are portraying as convincingly as they can.

LaBeouf used this approach when getting ready to play the heroic gunner Boyd 'Bible' Swan in Fury.

The film, which was based on real-life tank warfare stories, follows a number of US tank crews who are fighting Nazis in Germany during the final weeks of World War II.

LaBeouf's character was a very religious bloke who often quotes lines from the Bible and is seen as something of a spiritual guide to his comrades.

Shia LaBeouf in Fury (Sony)

In order to really understand who Swan was and what he was going through while on the frontline, the actor really pushed the boundaries with his behaviour, according to Bernthal.

During a previous appearance on an episode of The Joe Rogan Experience, Bernthal revealed that the Even Stevens actor would pull some shocking stunts on set.

He explained: "Shia at the time, he was a guy that, you know, when we did Fury together, that was such a wild experience.

"He was this guy who came in, he pulled his tooth out because he thought his character shouldn't have a tooth.

"He cut his face, he didn't shower for eight months."

Bernthal - who also 'isolated' himself while using method acting for his lead role in The Punisher - said he initially wondered if LaBeouf was just being performative - but that soon changed.

Jon Bernthal said he ended up really enjoying his co-star's efforts, even if they were pretty gruesome (Sony)

The 47-year-old continued: "At first, when I met him, I was like this guy's just f***ing loud, you know? He's wearing his process on his sleeve, showing everybody how hard he's working.

"But what I found after the eight months of working with him was somebody who – and it's just my own [opinion] – this thing is every bit as vital to him as it was for me.

"I found a real partner, I found a real kindred spirit. I found that he was willing to risk it all for the work."

Logan Lerman also previously told GQ a similar story about LaBeouf's method acting for Fury.

The Percy Jackson star explained: "He [LaBeouf] walks out into the hallway and says, ‘Hey man, wanna see something fun? Check this out…’ and he takes out a knife and cuts his face.

"For the whole movie, he kept opening these cuts on his face. That’s all real."

Well, you will never watch Fury the same again now, will you?